As a case in point, consider the open questions below for three of the most basic problems in the area, each of them with a long list of upper bounds spanning several decades: distance oracles [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}, dynamic shortest paths [12]}, [13]}, [14]}, [15]}, [16]}, [17]}, [18]}, [19]}, [20]}, [21]}, and shortest cycle (girth) [22]}, [23]}, [24]}, [25]}, [26]}, [27]}.
